 /*******************************************************************************
  * Copyright (c) 2000, 2005 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal.texteditor;

 import java.util.ArrayList ;
 import java.util.HashMap ;
 import java.util.List ;
 import java.util.Map ;

 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IExtensionPoint;
 import org.eclipse.core.runtime.Platform;

 import org.eclipse.ui.editors.text.EditorsUI;


 /**
  * Internal annotation super type hierarchy cache.
  * TODO this cache is currently unbound, i.e. only limited by the number of annotation types
  *
  * @since 3.0
  */
 public final class AnnotationTypeHierarchy {

     private Map fTypeMap;
     private Map fTypesCache= new HashMap ();

     public AnnotationTypeHierarchy() {
     }

     public AnnotationType getAnnotationType(String typeName) {
         AnnotationType type= (AnnotationType) fTypesCache.get(typeName);
         if (type == null) {
             String [] superTypes= computeSuperTypes(typeName);
             type= new AnnotationType(typeName, superTypes);
             fTypesCache.put(typeName, type);
         }
         return type;
     }

     public boolean isSubtype(String superType, String subtypeCandidate) {
         AnnotationType type= getAnnotationType(subtypeCandidate);
         return type.isSubtype(superType);
     }

     private String [] computeSuperTypes(String typeName) {
         ArrayList types= new ArrayList ();
         append(types, getDirectSuperType(typeName));
         int index= 0;
         while (index < types.size()) {
             String type= (String ) types.get(index++);
             append(types, getDirectSuperType(type));
         }

         String [] superTypes= new String [types.size()];
         types.toArray(superTypes);
         return superTypes;
     }

     private String getDirectSuperType(String typeName) {
         return (String ) getTypeMap().get(typeName);
     }

     private void append(List list, String string) {
         if (string == null || string.trim().length() == 0)
             return;

         if (!list.contains(string))
             list.add(string);
     }

     private Map getTypeMap() {
         if (fTypeMap == null)
             fTypeMap= readTypes();
         return fTypeMap;
     }

     private Map readTypes() {
         HashMap allTypes= new HashMap ();

         IExtensionPoint extensionPoint= Platform.getExtensionRegistry().getExtensionPoint(EditorsUI.PLUGIN_ID, "annotationTypes"); //$NON-NLS-1$
 if (extensionPoint != null) {
             IConfigurationElement[] elements= extensionPoint.getConfigurationElements();
             for (int i= 0; i < elements.length; i++) {
                 IConfigurationElement element= elements[i];

                 String name= element.getAttribute("name"); //$NON-NLS-1$
 if (name == null || name.trim().length() == 0)
                     continue;

                 String parent= element.getAttribute("super"); //$NON-NLS-1$
 if (parent == null || parent.trim().length() == 0)
                     parent= ""; //$NON-NLS-1$

                 allTypes.put(name, parent);
             }
         }

         return allTypes;
     }
 }

